Absorbent articles according to the present invention are articles which can be used to absorb any type of fluid. These articles include absorbent articles for personal hygiene (like for example sanitary napkins, pantyliners, tampons, inter labial articles, adult incontinence articles such as adult incontinence pads and diapers, baby diapers, breast pads and hemorrhoid pads). Other absorbent articles according to the present invention can be for example absorbent paper towels, wipes, toilet paper, or facial tissues. Such articles are commonly used to absorb and in some cases retain bodily fluids and other exudates excreted by the human body, such as urine, menses, fecal materials or mucus. Paper towels, wipes, facial tissues and toilet paper may be used also to absorb kitchen and food residues and/or any kind of dirt or waste. In many cases the absorbed materials, can be malodourant or can generate malodors with time while the article is still being used or after it has been thrown in the trash. Therefore, methods and materials for controlling and reducing malodors in absorbent articles have been developed. Fragrance materials have been widely used for this purpose, as well as ingredients such as silica or zeolites which are able to entrap some of the malodor generating molecules. The use of fragrance materials, however, tends to provide an overwhelming perfume scent to the product before use which may be undesirable in certain cases. The use of compounds capable of chemically reacting with the malodorous molecules and/or to interacting with nose receptors has also been described. However many of these compounds are very volatile or highly reactive so that it is difficult to preserve them within the article until the time the compound is needed for use, moreover the reactivity and the efficacy of these compounds varies significantly from one compound to the other and it is different when the source of malodor is different.
Some of these compounds have been also described as being incorporated into the absorbent articles as encapsulated materials (e.g. starch encapsulation) or as complexes with other molecules which, by way of complexation, reduce their volatility and protect their reactive sites. A typical example is the use of cyclodextrin complexes.
It is in general desired that the complexed or encapsulated compound is released upon wetting or use of the article, capsules are in general dissolved by wetting or broken by mechanical action thus releasing the compound. Wetting in general allows the complexed compounds to be released by the complexing molecule such as cyclodextrin. However only a limited number of compounds have been described which possess all the necessary properties so that they can at the same time form stable encapsulates or complexes in an effective manner and also be completely released when desired.
In addition, the known reactive compounds are often effective in reacting with malodourant molecules containing Nitrogen atoms (amine type odors, typically deriving from the degradation of urine) but less effective in reacting with malodourant molecules containing Sulphur atoms (thiol type malodors, typically associated with menstrual fluids and protein degradation).
There thus still remains a desire to provide new improved malodor control compositions for incorporation into absorbent articles. The improved malodor control compositions of the present invention contain new reactive compounds. These new reactive compounds form capsules/complexes in a complete fashion which are sufficiently stable upon storage when introduced into the absorbent articles, the reactive compounds are effectively released from the capsules/complex upon the occurrence of the desired trigger action (e.g. wetting or mechanical friction) and are able to neutralize malodors more effectively with respect to known compounds, including neutralizing a larger number of malodourant substances.
Encapsulation/complexation also beneficially prevents hydrophobic reactive compounds according to the present invention from negatively impacting absorbency or impacting the properties of adhesives or glues which might be present in the absorbent article e.g glues keeping several layers of the article together or, in the case of sanitary napkins and pantyliners, the panty fastening adhesive.
In addition to the advantages mentioned above the identification of new reactive compounds for use as encapsulated or complexed materials in absorbent articles will allow the formulators to have a broader palette of materials to choose from. Most of the known and new reactive compounds usable herein have an individual odor character once they are released from the complex, so that the addition of new ingredients to the palette from which a formulator can choose from allows them to develop more different and personalized perfume notes and accords.